Method for recording data on a data storage medium enabling data identification

ABSTRACT

The invention relates to methods for recording data on an information medium such as, for example a CD or DVD, and can be used for protecting data against non-authorised coping, identifying data storage media and for data validation. The inventive method consists in forming a data file in the form of a first data sector sequence, the sector addresses of the sequence being embodied in the form of a sequence of natural numbers, recording the first sequence of the formed sectors with respective addresses on a spiral track. In addition, during the formation of the first sector sequence, at least one second data sector sequence whose sector addresses at least partially coincide with the sector addresses of the first sequence is formed, the number of coinciding addresses is equal to C and is not less than the number of data sectors recorded on two adjacent turns of the spiral track in an area which corresponds to the addresses of the sectors. Key data is registered in sectors having the coinciding addresses. Any digital reader can be used for reading out data from the discs.

FIELD OF THE INVENTION

The group of inventions relates for methods of recording data on amedium whereby the data is recorded concentrically. These media can be,for example, CD or DVD discs. The group of inventions can be used forprotecting data recorded concentrically against illegal copying. Theinventions can be used further as a means to identify media, i.e., forexample, to determine whether the user has a legal or an illegal medium.These methods can be used still further to verify data recorded on mediawith identifying key data.

BACKGROUND ART

CD disc recording methods are known, where the authenticity of a CD isverified using a special equipment, which makes it possible to useillegal copies as authentic ones and to reformation recorded on a disc.

A CD ROM disc recording method is known, based on writing a program on aCD ROM disc to protect the information recorded on the disc againstillegal copying, whose cost is low, including the protectiveapplication. This program application is designed to handle a“protection key”, the disc being specifically processed duringmanufacturing to form a check ring. This system uses a special methodfor verifying the authenticity of the check ring. The insertion of thecheck ring using the authenticity verification makes it impossible tocopy a CD ROM disc even by a very sophisticated recording equipment.

This method offers many advantages as compared to other methods ofprotection, such as low cost combined with excellent protection.

The method can be also used to protect PC software designed to handle CDROMs and to operate in DOS or Windows (U.S. Pat. No. 6,101,476 A, G 06 F17/60, Aug. 8, 2000).

The known method has two features: a special way of manufacturing CDdiscs and the software for the disc authentication.

Methods of recording read-only data written on a CD ROM disc are known,whereby various check (key) data are written on a disc in addition todata for reading, this key data being extracted and used to restore thedata for reading but are lost when an attempt is made to copy the CD ROMdisc (WO 00 4053, G 11 B 20/00, Apr. 13, 2000; WO 00 62293, G 11 B20/00, Oct. 19, 2000; and WO 00 21086, G 11 B 20/00, Apr. 13, 2000).

The closest prior art of the invention is the method of data protectionaccording to U.S. Pat. No. 6,101,476 A.

The disadvantage of the prior art method is the presence of the discauthentication software, which increases the manufacturing cost whilethe part of the disc surface used to write the authentication programreduces the surface area for recording useful information.

SUMMARY OF THE INVENTION

The technical effect of the claimed data recording methods is expansionof the field of application of recording methods because any digitalreading equipment can be used to read data from discs. This featuresimplifies the verification procedure and reduces the cost of allservice equipment.

Thus the level of protection against copying is raised considerably.

Still another technical effect of the claimed methods is a greaterprotection of data recorded on media, the data becoming impossible toread from a copy made illegally. This method makes it possible not tofind any recording errors when such media are checked on a qualitycontrol apparatus during production, for example, to detect defects, orduring playback by a standard reading device, for example, a CD ROMdriver. The method ensures that data recorded on such media can be onlyread from an original disc made legally.

At the same time, the data can still be copied, for example, to a harddisc maintaining the initial recording standards, but to retrieve thesedata for further use by means of, for example, a CD ROM driver requiresthe presence of the original disc.

The technical effect in the first embodiment is accomplished by that, ina data recording method, a data file is formed for recording, whichcontains the first sequence of sectors with data, whose sector addressesrepresent a series of natural numbers; and the first sequence of theformed sectors with appropriate addresses is recorded on a spiral track,the file thus formed is written on a medium after forming and recordingat least one second sequence of data sectors to said file, the addressesof the sectors in the second sequence matching, at least in part, sectoraddresses of the first sequence, the number of the matching addressesbeing “c” and equaling at least the number of the data sectors recordedon two adjacent turns of the spiral track in an area that corresponds tothe addresses of these sectors, while the address of the first sector ofthe second sequence is selected to be equal to the address of the lastsector of the first sequence minus said number “c”, and the sectors ofthe second sequence with said addresses are written after the sectors ofthe first sequence are recorded.

In the process, the data for the recording are the user data and keydata, the former being intended for forming and recording the firstsequence of sectors and the second sequence with mismatching sectoraddresses, while the key data are intended for forming and recording thesectors of the second sequence with matching addresses.

The data medium is identified while reading the data or the key data ofthe second spiral track, whose address matches that in the firstsequence.

In the claimed embodiment of the method, the above-mentioned sectors ofthe second sequence can be written with an interval after the sectors ofthe first sequence.

A meander-shaped digital signal can be recorded in the interval on thespiral track.

The technical effect in the second embodiment is accomplished by that,in the data recording method consisting in forming a data file forrecording as the first sequence of data sectors, whose sector addressesrepresent a series of natural numbers, the first recording means writesthe first sequence of sectors formed with appropriate addresses on thefist spiral track, the second sequence of sectors with appropriateaddresses is formed, the formed first sequence is recorded up to asector with a specified address A1 and with an initially preset distancebetween adjacent turns of the spiral track with the recorded data, andthen this distance is changed in the process of recording to a value ofabout twice the initially preset distance between the turns of thespiral track, continuing the recording of the first sequence on thefirst track; the second recording means is set up at an initially presetdistance from the appropriate turn of the first track and data arewritten in parallel on the first spiral track and on the second spiraltrack of the sectors of the first sequence and of the second sequence,respectively, and when the sector A2≧A1+C is recorded, where C is thenumber of the data sectors that can be recorded on two adjacent turns ofthe spiral track, the recording on the second track is stopped, thedistance between the turns of the first track is changed to the value ofthe initially preset distance and the recording of the sectors of thefirst sequence is resumed, the addresses of the sectors of the firstsequence and the addresses of the second sequence with addresses from A1to A2 are matched.

In the process, the data for recording are the user data and key data,the former are intended for forming and recording the first sequence ofsectors, and the key data are intended for forming and recording thesectors of the second sequence.

The data medium is identified with specified data or key data from thesecond spiral track.

The technical effect in the third embodiment is accomplished by that, inthe data recording method consisting in forming a data file forrecording as the first sequence of sectors with data, whose sectoraddresses represent a series of natural numbers, the first sequence ofsectors formed with appropriate addresses is recorded on the firstspiral track, the second sequence of sectors with appropriate addressesis formed, the first formed sequence is recorded up to a sector with aspecified address A1 and with an initially preset distance betweenadjacent turns of the first spiral track, and then this distance ischanged in the process of recording at least to a value that is twicethe initially preset distance; after the sector of the first sequencewith the address A2≧A1+C is written, this distance is changed to theinitially preset value and the recording of the first sequence iscontinued to the end; after the first sequence is recorded, therecording means is returned to the area of the recorded sector with theaddress A1 on the spiral track and this means is offset relative to thefirst track by the value of the initially preset distance between theturns of revolutions of the first spiral track, and the second sequenceof sectors is recorded in the interval between the turns of the firstspiral track with the recorded sectors of the first sequence, therecording on the second track being stopped when the sector A2≧A1+C iswritten, where C is the number of data sectors that can be recorded ontwo adjacent turns of the spiral track.

Here, the data for recording on the disc are the user data and key data,the former are intended for forming and recording the first sequence ofsectors, and the key data are intended for forming and recording sectorsof the second sequence. The identification is carried out as data isread from the second spiral track.

EXAMPLES OF EMBODIMENTS

The method according to the first embodiment is based on that the datarecording on a spiral track forms turns of this track as sectors withdata. The data is formed as a file which is a sequence of data sectorsprovided with addresses. The sequence of the addresses of such sectorsis normally a natural series of numbers. A specific feature of a readingdevice is that when a certain sector address is specified and issearched, the reading device calculates its own movement relative to thelatest location and can move along the radius of a track by the numberof sectors of no less than the number “c” that is equal or correspondsto the number of the sectors which were recorded on adjacent turns ofthe spiral track.

Given these prerequisites, the first embodiment of the method isproposed, wherein data files are formed as the first sequence of datasectors before the data are recorded, the addresses of the sectorsrepresenting a natural series of numbers, for example, in the followingform:

-   -   N, N+1, N+2, . . . , N+n

Then, at least one second sequence of data sectors is formed as:

-   -   N+1, N+2, . . . , N+n, N+n+1, N+n+2, . . . , and the addresses        of the sectors N+1, N+2, . . . , N+n is the second sequence        match, at least in part, the addresses of sectors in the first        sequence, the number of the matching addresses being equal to or        of the same order with “c”, which corresponds to the number of        data sectors recorded on any two adjacent turns of the spiral        track, while the address of the first sector N+1 in the second        sequence is selected to be equal to the address of the last        sector N+n in the first sequence minus the number “c” and the        above-mentioned file is formed by recording sectors of the        second sequence with these addresses after the sectors of the        first sequence are recorded. Then the file thus formed is        written to the medium. The medium is verified as it is read by a        standard reading apparatus.

It should be noted that, while manufacturing the medium and recordingthe user data, the reading program data to be rewritten to the memory ofthe reader-controlling computer, which data are used in reading datafrom the medium, are also recorded on the disc.

Thus, data are read from the medium using the data of the readingprogram, which include also the data about the sectors with matchingaddresses, with the help of which the reader determines the legality ofa disc and also utilized the key data to ensure the use of the userdata.

Reading according to the first embodiment can be carried out as follows.It was stated above that, while searching for a specified sectoraddress, the reader calculates the value of relative movement of thereading head relative to its latest location (the last address itpassed).

The sequence of data reading by the reader in accordance with the dataof said reading program is as follows.

The address of a sector in the first sequence, which does not match theaddresses of the second sequence, is specified for indirect positioningof the reading head (binding to the latest reading address). Then theaddress of a sector in the first sequence, which is one of the matchingaddresses, is specified and this sector in the first sequence is found.Then the address of a sector in the second sequence, which does notmatch the addresses of the first sequence, is specified whereupon thesector containing key data with the specified address in the secondsequence is found when an address that matches these matching addressesof the first sequence and of the second sequence is specified, the keydata provide further use of the data.

As it was mentioned above, normal data for recording on a medium includeuser data and key data, and the former can be used, for example, forforming and recording the first sequence of sectors, while the key dataare intended for forming and recording the sectors of the secondsequence with matching addresses. And the second sequence can include,in addition to the sectors with matching addresses, also the user data.It should be noted that it is preferred that the key data be recorded inthe sectors with matching addresses in the first sequence and secondsequence as data are written on a medium because the data in the sectorswith matching addresses of the second sequence will be lost when anattempt is made to manufacture the medium illegally.

The method can be realized with an additional protection againstcopying. For this purpose, said sectors of the second sequence arerecorded with an interval after the sectors of the first sequence.

This interval can be a digital signal recorded on a spiral track in theform of a meander and this signal will make data reading for copyingstill more difficult.

That is, data can be recorded between the first sequence and secondsequence with a short time delay for the period of automatic “gap”between the sequences; in this case the data of the sectors withmatching addresses in the matching addresses in the second sequence willnot be read in the process of copying (to an illegal disc).

In other words, the insertion of a “hole”, i.e., the absence of data,between the first sequence and the second sequence of a sector resultsin during an attempt at copying a disc with such a “hole” these datafrom sectors being “read” will be written onto the copy of the discinstead of the “hole” and data from a certain part of the sectors beyondthe “hole”, i.e., data with matching addresses, will be lost.

Thus, recording data to the sectors whose addresses make a certainsequence (1), (2) or a sequence of sectors with missing data in anappropriate area of a track, i.e. “hole”, can ensure even betterprotection of the data on a disc against copying because, if the disc islegal, the data will be read according to the reading program takinginto account the special features of recording; hence the data thus readcan be used further, while the key data will be lost in coping (to anillegal disc). So, the verification, including identification of thedata medium, is carried out during data reading. It means that, if adisc is illegal, it will be read in copying by a standard reading devicewithout the specific features of the original recording, and thus thedata will be unusable further.

The realization of the method in the second and third embodimentsinvolves the following actions.

It is worth repeating that a spiral track is formed as data is recordedon a disc. Pits located in a row form a recording track with appropriateinformation in the digital format. The minimum length of a pit is 0.9microns. The distance between adjacent turns of the track in a digitaldisc is 1.6 microns, which corresponds approximately to 625 tracks(revolutions of a track) per 1 mm. As a disc is scanned by a laser, itsbeam is reflected completely back in the areas that do not have pitswhile the pit areas scatter the beam, and these signals are sensed by aphotoelectric detector and converted to appropriate digital signalswhich are used then to transform the data being read into sound, images,etc. And the data reading from the optical disc is controlled by apreset reading program that moves the reading head relative to thedata-containing spiral tracks of the disc.

Modern digital reader-players can control the reading process being ableto find the beginning of a record fragment (sector address) and to readthe data in the sector. Hence, it is possible to have different discrecording modifications using standard recording devices and standardreading devices. Data can be recorded on tracks, for example, whileinserting additional tracks, although it is necessary to take intoaccount the requirements for disc recording density in this case.

In addition, to read data from a medium, the memory of the computer thatcontrols the reading equipment contains a reading program that in datareading process reads also data from the medium to be stored in thecomputer memory, this data being intended for using the data recorded onthe medium.

In view of this circumstances, the recording method in the secondembodiment can be used as follows. First, the user data and key data,i.e., data to be recorded on a medium, form data files as the firstsequence of sectors with the user data. The addresses of the sectors inthe first sequence normally represent a natural series of numbers, andin addition they form the second sequence of sectors with the key data,the sectors being provided with appropriate addresses.

The first sequence of the sectors with appropriate addresses thus formedstarts to be recorded as the first spiral track, the recording beingcarried out by a recording means with a standard distance (pitch)between the adjacent turns of the spiral track (the initially presetdistance is normally about 2.4 microns). As data is recorded in asector, for example, with the address A1, the above distance isgradually changed in the process of recording to a value of about twicethe initially preset distance, and the data of the first sequence to berecorded on the first track. Then the second recording means is switchedon at the initially preset distance from the turn of the first spiraltrack in the area where no data was recorded yet, and the data of thesecond sector sequence starts to be recorded by the second recordingmeans on the second spiral track located between the turns of the firsttrack in parallel to the record on the first track. And the distance, asit was mentioned above, between the turns of the first track and secondtrack with the recorded data of the first sequence and second sequencecorresponds to the initially preset distance. When the sector A2≧A1+C isrecorded, where C is the number of data sectors that can be recorded ontwo adjacent turns of the spiral, the recording on the second track isstopped, the distance between the turns of the first track is changed tothe value of the initially preset distance and the recording of thesectors in the first sequence is resumed. The addresses of the firstsequence and the addresses of the second sequence on the first andsecond tracks from A1 to A2 are matched.

Thus, the data will be recorded in the area of the spiral track on twotracks of the medium starting from the address of approximately sectorsA1 to A2. As it was mentioned above, it is preferred that the user datashould be recorded on the first track, while the key data should berecorded on the second additional track between the turns of the firsttrack. The third embodiment of the method differs from the second in thesequence of actions when data is recorded on the first and secondtracks.

In the third embodiment, a data file is also formed first as the firstsequence of sectors with data provided with appropriate addressesrepresenting, for example, a natural series of numbers. The secondsequence of data sectors is also formed, the sectors being provided withappropriate addresses. One recording means is used for this method. Datais recorded on a medium with the help of one recording means. The firstsequence of the formed sectors with appropriate addresses is recorded inthe form of the first spiral track. The first formed sequence isrecorded up to a sector with the specified address A1 and with aninitially preset distance between the adjacent turns of the spiral trackwith the recorded data, then this distance is increased in the processof recording to a value of double initially preset distance between theadjacent turns of the first track and the recording continues up to theaddress A2≧A1+C whereupon this distance is changed to the initiallypreset one, the recording of the first sequence on the first track isresumed; after the first sequence is recorded the recording means istransferred to the area of the address of sector A1 with the increaseddistance between the turns of the first track, and the second sequenceof sectors is recorded.

Thus, the data of the first sequence of sectors and of the secondsequence of sectors will be recorded on the medium starting from asector with the address A1 to a sector with the address A2, i.e. thedata of the sectors in the second sequence will be recorded in aninterval between the turns of the first track with the recorded data ofthe sectors in the first sequence, the addresses of the sectors in thefirst sequence and the addresses of the sectors in the second sequenceare matched on the first and second tracks from A1 to A2 in this area.

The data recorded on a medium in the second embodiment and in the thirdembodiment is verified while reading the data by a reading device asfollows.

As it was mentioned, hidden data, which is normally the key data, isrecorded on a medium on the second spiral track located between theturns of the first spiral track.

In this area, the addresses of the sectors of the first sequencerecorded on the first track and of the second sequence recorded on thesecond track match; these are addresses from A1 to A2, while A2≧A1+Cwhere C is the number of sectors, which can be recorded on two adjacentturns of a track in the area of appropriate addresses. By specifying acertain sequence of addresses in this area to a reading device, a sectorwith one of the addresses from A1 to A2 in the second sequence of thedata recorded on the second track can be found out by successiveapproximations. It is done as follows. Indirect positioning is carriedout, for example, by finding a sector in the first sequence, forexample, with an address up to A1. In this case, the reading device islocated, for example, towards the center of the concentric recordrelative to the second track.

Since the reading device calculates its movement relative to its latestposition (the number of spiral track turns that the reading device-hasto cross) while data reading in order to move to the recorded area inthe track with sectors whose addresses are less than specified addressesby the value “c”, then an address between A1 and A2 is specified to thereading device, the reading device moves to the area with matchingaddresses. In this case, the reading device can get to the sector withthe matching address recorded on the second track by searching addressesfirst up the address A1, then any of those addresses that match A1 up toA2, and then an address greater than A2, meanwhile constantlypositioning itself. To improve the accuracy of determining, finding, andsubsequent reading data in the second track, each of the sectors withthe addresses A1 to A2 in the second sequence is provided with a checkcharacter or characters. And as the reading device reads data from thesectors specified to it in the process of the search, it constantlychecks the data for the presence of the check character. Having foundthis character, the reading device reads the data.

In case data is read from any of the sectors in the second sequence, themedium is simultaneously identified. And the reading device can issue amessage, for example, that the medium is legal.

INDUSTRIAL APPLICABILITY

The present invention allows to verify the authenticity of discs withoutusing special equipment and can be widely used in manufacturing CD orDVD discs.

1. A method for recording data on a medium, in which a data file forrecording is formed, said file containing the first sequence of sectorswith data, whose sector addresses represent a series of natural numbers,for recording the first sequence of the formed sectors with appropriateaddresses on a spiral track, characterized in that the formed file isrecorded on a medium after at least one second sequence of sectors withdata was formed and was recorded to said file, the addresses of thesectors in the second sequence matching at least in part the addressesof sectors in the first sequence, the number of the matching addressesbeing “c” and equaling at least the number of data sectors recorded intwo adjacent turns of a spiral track in the area that corresponds to theaddresses of these sectors, and the address of the first sector in thesecond sequence being selected to be equal to the address of the lastsector in the first sequence minus said number “c” and the sectors inthe second sequence with said addresses being recorded after recordingthe sectors in the first sequence.
 2. A method as claimed in claim 1characterized in that the data for recording include the user data andkey data, the former are intended for forming and recording the firstsector sequence and the second sequence with mismatching sectoraddresses, and the key data are intended for forming and recording thesectors of the second sequence with matching addresses.
 3. A method asclaimed in claim 1 or in claim 2 characterized in that a medium isidentified as data or the key data is read from the second spiral track.4. A method as claimed in claim 1 or in claim 2 characterized in thatsaid sectors of the second sequence are recorded with an interval afterthe sectors of the first sequence.
 5. A method as claimed in claim 4characterized in that a digital signal in the form of a meander isrecorded in said interval on the spiral track.
 6. A method for recordingdata on a medium, which consists in that a data file is formed forrecording as the first sequence of sectors with data, whose sectoraddresses represent a series of natural numbers, for recording the firstsequence of the formed sectors with appropriate addresses on the spiraltrack characterized in that the second sequence of sectors withappropriate addresses is formed, a recording means records the firstformed sequence on the first spiral track up to a sector with aspecified address A1 and with an initially preset distance betweenadjacent turns of the spiral track with the recorded data, then saiddistance is changed in the process of recording to a value of abouttwice the initially preset distance between the turns of the spiraltrack, the second recording means is set up while the first sequence isstill being recorded on the first track at the initially preset distancefrom the appropriate turn of the first track, and the data are recordedin parallel to the sectors in the first sequence and second sequence onthe first spiral track and on the second spiral track, respectively, andwhen the sector A2≧A1+C, where C is the number of the data sectors thatcan be recorded on two adjacent turns of a spiral track, is recorded,the recording on the second track is stopped, the distance between theturns of the first track is changed to the initially preset distance,and the recording of the sectors in the first sequence is continued, theaddresses of sectors in the first sequence and the addresses of sectorsin the second sequence on the first and second spiral tracks from A1 toA2 are matched.
 7. A method as claimed in claim 6 characterized in thatdata for recording on a disc include the user data and key data, theformer are intended for forming and recording the first sequence ofsectors and the key data are intended for forming and recording sectorsin the second sequence.
 8. A method as claimed in claim 6 or 7,characterized in that a medium is identified as data or key data is readfrom the second spiral track.
 9. A data recording method enablingidentification, which consists in that a data file for recording isformed as the first sequence of sectors with data, whose sectoraddresses represent a series of natural numbers, for recording the firstsequence of the formed sectors with appropriate addresses on a spiraltrack, characterized in that the second sequence of sectors withappropriate addresses is formed, the first formed sequence is recordedto a sector with the specified address A1 and with an initially presetdistance between adjacent turns of the first spiral track, then saiddistance is increased in the process of recording to a value of at leasttwice the initially preset distance, after the sector of the firstsequence with the address A2≧A1+C is recorded said distance is changedto the initially preset distance and the recording of the first sequencecontinues to the end; the first sequence having been recorded on thefirst spiral track, the recording means is returned to the area wherethe sector with the address A1 was recorded and the writing head isoffset relative to the first spiral track by the value of the initiallypreset distance between the turns of revolutions of the first spiraltrack, the second sequence of sectors is recorded in an interval betweenthe turns of the first spiral track and the recording on the secondtrack is stopped when the sector A2≧A1+C is recorded, where C is thenumber of the data sectors that can be recorded on two adjacent turns ofthe spiral track in the area of the sectors with said addresses, thesectors in the first sequence matching the sectors in the secondsequence on the first and second spiral tracks from A1 to A2.
 10. Amethod as claimed in claim 9 characterized in that data for recordinginclude the user data and key data, the former are intended for formingand recording the first sequence of sectors, and the key data areintended for forming and recording sectors in the second sequence.
 11. Amethod as claimed in claim 9 or 10 characterized in that a medium isidentified as data or key data is read on the second spiral track.